UHF频段射频识别系统天线研究
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摘要
利用射频信号对物体进行自动识别的射频识别(Radio FrequencyIdentification,RFID)技术是一项正在迅速发展的技术,尤其是UHF频段的RFID技术发展很快。随着RFID系统工作频率的提高,天线设计变得越来越重要。本文研究了UHF频段RFID系统的天线技术,主要工作及创新点如下:
首先,本文研究了标签天线及读写器天线设计的理论方法,并重点研究了标签天线设计理论。研究结果表明,为保证标签天线的基本读写距离,在设计标签天线时,需要首先考虑天线增益和标签天线到芯片的功率传输系数,提高功率传输系数的途径就是调整标签天线与芯片的输入阻抗并使它们尽可能实现共轭匹配。
其次,本文研究并设计了一种低成本小型化的UHF频段RFID标签天线,天线为变形偶极子形式。可以采用调节短路线的方式调节天线的输入阻抗,本文以此方法设计的标签天线输入阻抗实部可以在30到50Ω范围内调节,虚部在150到300Ω范围内调节,可以满足天线与大多数芯片的共轭匹配要求。另外通过弯曲偶极子的两臂可以对天线进行小型化设计,本文以此方法设计的标签天线尺寸为52mm×44mm×0.5mm,相比同类型其它标签天线,尺寸减小了40%左右。另外由于采用对称设计,天线主辐射方向指向标签的正反面方向,这样便于读写器识别标签。最后本文制作了所设计的标签天线并分析了标签天线的输入阻抗测量方法。
再次,本文研究并设计了一种低成本小型化的UHF频段RFID读写器天线。采用上贴片挖孔、增加介电常数的方式来减小天线的尺寸,并深入研究了天线的各个尺寸参数对天线性能的影响,指出天线性能对上表面贴片边长d、挖孔宽度e以及介电常数ε的变化比较敏感。文中最后优化的天线在2dB增益情况下,天线尺寸在110mm×110mm×3mm左右,相比较于同类型参考天线,面积减小了近70%,阻抗带宽提高75%左右,轴比带宽提高60%左右。同时还可以根据增益大小的需要调整天线的尺寸。最后本文制作了其中两组参数的读写器天线,回波损耗的测试结果与仿真结果吻合较好,验证了设计方法的有效性。
Radio Frequency Identification(RFID) which uses radio frequency singals for automatic identification of objects is a rapidly developing technology, especially UHF band RFID technology. With the frequency of RFID system increasing, antenna design has become more and more important. Antenna technology on the UHF band RFID system is studied in this thesis, and the main work and innovation points include:
Firstly, theoretical methods of the tag antenna and the reader antenna design are investigated and the emphasis is placed on the tag antenna. The result indicates that radiation gain and power transmission coefficient from tag antenna to chip should be considered in the first place in order to ensure the basic reading and writing distance of the tag. The way to improve power transmission coefficient is to design the tag antenna and make sure its input impedance conjugate matching to the chip input impedance.
Secondly, a kind of low-cost miniaturized UHF band RFID tag antenna with the form of transformative dipole is studied and designed in this thesis. Its input impedance can be regulated by adjusting antenna short line. The real and imaginary part of tag antennas designed by the method in this thesis can be regulated from 30 to 50Ωand from 150 to 300Ωrespectively, which can meet the requirement of conjugate matching between the tag antennas and most chips. In addition, miniaturization design of the antenna can be carried out by bending two arms of the dipole. The size of the tag antenna optimized by this method in this thesis is 52mm×44mm×0.5mm and reduced by 40 percents comparing with other tag antennas of the same kind. Because of symmetrical design, the main radiation direction points to the front and back sides of the tag which makes it easy for the tag to be read by the reader. The designed tag antenna is fabricated finally and the measurement method of input impedance is analyzed.
Thirdly, a kind of low-cost miniaturized UHF band RFID reader antenna, the size of which can be miniaturized by the patch hole digging and increasing the permittivity, is also studied and designed in this thesis. Furthermore, the influences on the antenna performance by all kinds of antenna parameters are further researched and that performance of the antenna is sensitive to the length of top patch side d, the width of patch dig hole e and the permittivityεis indicated. The size of the optimized antenna is about 110mm×110mm×3mm while the gain is 2dB, which size is reduced by 70 percents and bandwidth of return loss and axial ratio is increased by 75 percents and 60 percents respectively comparing with the same kind reader antenna. Meanwhile, the size can be adjusted according to the demand of gain. The designed reader antennas in two kinds of parameters are fabricated finally. The measured and the simulated results are in good agreement and validity of the design method is proved.
首先,本文研究了标签天线及读写器天线设计的理论方法,并重点研究了标签天线设计理论。研究结果表明,为保证标签天线的基本读写距离,在设计标签天线时,需要首先考虑天线增益和标签天线到芯片的功率传输系数,提高功率传输系数的途径就是调整标签天线与芯片的输入阻抗并使它们尽可能实现共轭匹配。
其次,本文研究并设计了一种低成本小型化的UHF频段RFID标签天线,天线为变形偶极子形式。可以采用调节短路线的方式调节天线的输入阻抗,本文以此方法设计的标签天线输入阻抗实部可以在30到50Ω范围内调节,虚部在150到300Ω范围内调节,可以满足天线与大多数芯片的共轭匹配要求。另外通过弯曲偶极子的两臂可以对天线进行小型化设计,本文以此方法设计的标签天线尺寸为52mm×44mm×0.5mm,相比同类型其它标签天线,尺寸减小了40%左右。另外由于采用对称设计,天线主辐射方向指向标签的正反面方向,这样便于读写器识别标签。最后本文制作了所设计的标签天线并分析了标签天线的输入阻抗测量方法。
再次,本文研究并设计了一种低成本小型化的UHF频段RFID读写器天线。采用上贴片挖孔、增加介电常数的方式来减小天线的尺寸,并深入研究了天线的各个尺寸参数对天线性能的影响,指出天线性能对上表面贴片边长d、挖孔宽度e以及介电常数ε的变化比较敏感。文中最后优化的天线在2dB增益情况下,天线尺寸在110mm×110mm×3mm左右,相比较于同类型参考天线,面积减小了近70%,阻抗带宽提高75%左右,轴比带宽提高60%左右。同时还可以根据增益大小的需要调整天线的尺寸。最后本文制作了其中两组参数的读写器天线,回波损耗的测试结果与仿真结果吻合较好,验证了设计方法的有效性。
Radio Frequency Identification(RFID) which uses radio frequency singals for automatic identification of objects is a rapidly developing technology, especially UHF band RFID technology. With the frequency of RFID system increasing, antenna design has become more and more important. Antenna technology on the UHF band RFID system is studied in this thesis, and the main work and innovation points include:
Firstly, theoretical methods of the tag antenna and the reader antenna design are investigated and the emphasis is placed on the tag antenna. The result indicates that radiation gain and power transmission coefficient from tag antenna to chip should be considered in the first place in order to ensure the basic reading and writing distance of the tag. The way to improve power transmission coefficient is to design the tag antenna and make sure its input impedance conjugate matching to the chip input impedance.
Secondly, a kind of low-cost miniaturized UHF band RFID tag antenna with the form of transformative dipole is studied and designed in this thesis. Its input impedance can be regulated by adjusting antenna short line. The real and imaginary part of tag antennas designed by the method in this thesis can be regulated from 30 to 50Ωand from 150 to 300Ωrespectively, which can meet the requirement of conjugate matching between the tag antennas and most chips. In addition, miniaturization design of the antenna can be carried out by bending two arms of the dipole. The size of the tag antenna optimized by this method in this thesis is 52mm×44mm×0.5mm and reduced by 40 percents comparing with other tag antennas of the same kind. Because of symmetrical design, the main radiation direction points to the front and back sides of the tag which makes it easy for the tag to be read by the reader. The designed tag antenna is fabricated finally and the measurement method of input impedance is analyzed.
Thirdly, a kind of low-cost miniaturized UHF band RFID reader antenna, the size of which can be miniaturized by the patch hole digging and increasing the permittivity, is also studied and designed in this thesis. Furthermore, the influences on the antenna performance by all kinds of antenna parameters are further researched and that performance of the antenna is sensitive to the length of top patch side d, the width of patch dig hole e and the permittivityεis indicated. The size of the optimized antenna is about 110mm×110mm×3mm while the gain is 2dB, which size is reduced by 70 percents and bandwidth of return loss and axial ratio is increased by 75 percents and 60 percents respectively comparing with the same kind reader antenna. Meanwhile, the size can be adjusted according to the demand of gain. The designed reader antennas in two kinds of parameters are fabricated finally. The measured and the simulated results are in good agreement and validity of the design method is proved.
引文
[1]周晓光,王晓华.射频识别(RFID)技术原理与应用实例.北京:人民邮电出版社,2006:11,2
[2]郎为民.射频识别(RFID)技术原理与应用.北京:机械工业出版社,2006:1
[3]尹应增.微波射频技术研究.西安:西安电子科技大学,2002:1
[4]http://www.invengo.cn/
[5]http://www.systron.com.cn/
[6]游战清,刘克胜,吴翔,林汉宏.无线射频识别(RFID)与条码技术.北京:机械工业出版社,2006:3
[7]Klaus Finkenzeller(德)著,吴晓峰,陈大才译.射频识别技术.北京:电子工业出版社,2006:44,116-124.
[8]Sanming Hu;Choi Look Law;Wenbin Dou."Measurements of UWB Antennas Backscattering Characteristics for RFID Systems." Ultra-Wideband,2007.ICUWB 2007.IEEE International Conference on.Singapore.2007:94-99
[9]Hu Sanming;Law Choi Look;Dou Wenbin;Chen Honghui."Detection Range Enhancement of UWB RFID Systems." Anti-counterfeiting,Security,Identification,2007 IEEE International Workshop.2007:431-434
[10]Hu S;Law C L;Dou W."Petaloid antenna for passive UWB-RFID tags." Electronics Letters.2007.Vol:43
[11]慈新新,王苏滨,王硕.无线射频识别(RFID)系统技术与应用.北京:人民邮电出版社,2007:3
[12]Stockman H."Communication by means of reflected power."Proceedings of the IRE,1948.Vol:36,Issue:10:1196-1204,.
[13]D.B.Harris."Radio transmission system with modulatable passive responder,"U.S.Patent.2 927321,1960
[14]R.F.Harrington."Theory of loaded scatterers," Proc.Inst.Elect.Eng.1964.Vol:111,No.4:617-623
[15]Udo Karthaus;Martin Fischerfully."Integrated passive UHF rfid transponder ic with 16.7 uw minimum RF input power."Solid-State Circuits,IEEE Journal of.2003.Vol:38,No.10:1602-1608
[16]K.V.S.Rao;Pavel V.Nikitin;SanderF.Lam."Impedance Matching Concepts in RFID Transponder Design." Automatic Identification Advanced Technologies,Fourth IEEE Workshop.2005:39-42
[17]K.V.Seshagiri Rao;Pavel V.Nikitin;Sander F.Lam."Antenna design for UHF RFID tags:a review and a practical application." IEEE Transactions on Antennas and Propagation.2005.Vol:53,No.12:3870-3876
[18]Pavel V.Nikitin;K.V.S.Rao."Reply to 'Comments on Antenna Design for UHF RFID Tags A Review and a Practical Application'." IEEE Transactions on Antennas and Propagation.2006.Vol:54,No.6:1906-1907
[19]卢万铮.天线理论与技术.西安:西安电子科技大学出版社,2004:231-233
[20]吕英华.计算电磁学的数值方法.北京:清华大学出版社,2004:260
[21]Li Yang;S.Serkan Basat;Manos M.Tentzeris."Design and Development of Novel Inductively Coupled RFID Antennas." Antennas and Propagation Society International Symposium.2006:1035-1038
[22]Tikhov Y;Yongjin Kim;Young-Hoon Min."A novel small antenna for passive RFID transponder" Microwave Conference,European.2OO5.Vol:1:4
[23]Yuri Tikhov;Yongjin Kim;Young-Hoon Min."Compact Low Cost Antenna for Passive RFID Transponder." Antennas and Propagation Society International Symposium.2006:1015-1018
[24]C.C.Chang;Y.C.Lo."Broadband RFID tag antenna with capacitively coupled structure."Electronics Letters.2006.Vol:42,Issue 23:1322-1323
[25]Ibrahiem A;Tan-Phu Vuong;Ghiotto A;Tedjini S."New design antenna for RFID UHF tags."Antennas and Propagation Society International Symposium 2006,IEEE.2006:1355-1358
[26]Yamada Y;Jung W.H;Naobumi Michishita."Extremely Small Antennas for RFID Tags."Communication systems,2006.ICCS 2006.10th IEEE Singapore International Conference on.Singapore.2006:1-5
[27]Jeon S;Yu Y;Choi J."Dual-band slot-coupled dipole antenna for 900MHz and 2.45 GHz RFID tag application" Electronics Letters.2006.Vol:42:1259-1260
[28]Zhang M.T;Jiao Y.C;Zhang F.S."Dual-band CPW-fed folded-slot monopole antenna for RFID application" Electronics Letters.2006.Vol:42:1193-1194
[29]L.S.Chan;K.W.Leung;R.Mittra;K.V.S.Rao."Platform-tolerant Design for an RFID Tag Antenna".Anti-counterfeiting,Security,Identification,2007 IEEE International Workshop.Xizmen,China.2007:57-60
[30]Pavel V.Nikitin;Sander Lam;K.V.S.Rao."Low Cost Silver Ink RFID Tag Antennas."Antennas and Propagation Society International Symposium 2005,IEEE.2005:353-356
[31]Pavel V.Nikitin;K.V.Seshagiri Rao;Sander F.Lam;Vijay Pillai;Rene Martinez;Harley Heinrich."Power Reflection Coefficient Analysis for Complex Impedances in RFID Tag Design." Microwave Theory and Techniques,IEEE Transactions.Vol:53,Issue:9.2005:2721-2725
[32]Steven M.Weigand."Compact Microstrip Antenna with Forward-Directed Radiation Pattern for RFID Reader Card." Antennas and Propagation Society International Symposium,2005IEEE.2005:337-340
[33]Choon Sac Lee;Nalbandian V."Planar circularly polarized microstrip antenna with a single feed." Antennas and Propagation,IEEE Transactions.1999.Vol:47,Issue:6:1005-1007
[34]Suwalak R;Phongcharoenpanich C."Circularly polarized truncated planar antenna with single feed for UHF RFID reader." Communications,2007.APCC 2007.Asia-Pacific Conference on.Bangkok.2007:103-106
[35]Nasimuddin;Esselle K.P;Verma A.K."Wideband High-Gain Circularly Polarized Stacked Microstrip Antennas With an Optimized C-Type Feed and a Short Horn." Antennas and Propagation,IEEE Transactions.2008.Vol:56,Issue:2:578-581
[36]Jong Moon Lee;Nae Soo Kim;Cheol Sig Pyo."A Circular Polarized Metallic Patch Antenna for RFID Reader." Communications,2005 Asia-Pacific Conference on.2005:116-118
[37]Fa-Shian Chang;Kin-Lu Wong;Tzung-Wern Chiou."Low-cost broadband circularly polarized patch antenna." Antennas and Propagation,IEEE Transactions.2OO3.Vol:51,Issue:10:3006-3009
[38]We-Shyang Chert;Chun-Kun Wu;Kin-Lu Wong."Single-feed square-ring microstrip antenna with truncated corners for compact circular polarisation operation." Electronics Letters.1998.Vol:34:1045-1047
[39]Jieh-Sen Kuo;Gui-Bin Hsieh."Gain enhancement of a circularly polarized equilateral-triangular microstrip antenna with a slotted ground plane." Antennas and Propagation,IEEE Transactions.2003.Vol:51,Issue:7:1652-1656
[40]Jui-Han Lu;Chia-Luan Tang;Kin-Lu Wong."Single-feed slotted equilateral-triangular microstrip antenna for circular polarization." Antennas and Propagation,IEEE Transactions.1999.Vol:47,Issue:7:1174-1178
[41]Row J.-S;Ai C.-Y."Compact design of single-feed circularly polarised microstrip antenna."Electronics Letters.2004.Vol:40:1093-1094
[42]Yim H.-Y.A;Kong C.-P;Cheng K.-K.M."Compact circularly polarised microstrip antenna design for dual-band applications." Electronics Letters.2006.Vol:42:380-381
[43]张明涛.“应用于RFID系统的天线设计”[学位论文].西安:西安电子科技大学.2007:34-35
[44]Dongmin Shin;Piljun Park;Wonmo Seong;Jaehoon Choi."A Novel Dual-band Circularly Polarized Antenna Using a Feeding Configuration for RFID Reader." Electromagnetics in Advanced Applications,2007.ICEAA 2007.International Conference.2007:511-514
[45]Jazi M.N;Azarmanesh M.N."Design and implementation of circularly polarised microstrip antenna array using a new serial feed sequentially rotated technique." Microwaves,Antennas and Propagation,IEE Proceedings.2006.Vol:153:133-140
[46]Griffin J.D;Durgin G.D."Gains For RF Tags Using Multiple Antennas." Antennas and Propagation,IEEE Transactions.2OO8.Vol:56,Issue:2:563-570
[47]Yamada Y;Hong W.G;Jnng W.H;Michishita N."High gain design of a very small normal mode helical antenna for RFID tags." TENCON 2007-2007 IEEE Region 10Conference.2007:1-4
[48]You Chung Chung;Kyounghwan Lee."2.4GHz Yagi-Uda RFID tag antenna design with low back-lobe using genetic algorithm." Radio and Wireless Symposium,2008 IEEE.2008:475-478
[49]赖晓铮.“UHF频段射频识别系统与天线研究”[学位论文]广州:华南理工大学.2006:71
[50]Bo Gao;Chi Ho Cheng;Yuen M.M.F;Murch R.D."Low Cost Passive UHF RFID Packaging with Electromagnetic Band Gap(EBG)Substrate for Metal Objects." Electronic Components and Technology Conference,2007.ECTC '07.Proceedings.57th.2007:974-978
[51]Ukkonen L;Sydanheimo L;Kivikoski M."Patch antenna with EBG ground plane and two-layer substrate for passive RFID of metallic objects." Antennas and Propagation Society International Symposium,2004.IEEE.2004.Vol:1:93-96
[2]郎为民.射频识别(RFID)技术原理与应用.北京:机械工业出版社,2006:1
[3]尹应增.微波射频技术研究.西安:西安电子科技大学,2002:1
[4]http://www.invengo.cn/
[5]http://www.systron.com.cn/
[6]游战清,刘克胜,吴翔,林汉宏.无线射频识别(RFID)与条码技术.北京:机械工业出版社,2006:3
[7]Klaus Finkenzeller(德)著,吴晓峰,陈大才译.射频识别技术.北京:电子工业出版社,2006:44,116-124.
[8]Sanming Hu;Choi Look Law;Wenbin Dou."Measurements of UWB Antennas Backscattering Characteristics for RFID Systems." Ultra-Wideband,2007.ICUWB 2007.IEEE International Conference on.Singapore.2007:94-99
[9]Hu Sanming;Law Choi Look;Dou Wenbin;Chen Honghui."Detection Range Enhancement of UWB RFID Systems." Anti-counterfeiting,Security,Identification,2007 IEEE International Workshop.2007:431-434
[10]Hu S;Law C L;Dou W."Petaloid antenna for passive UWB-RFID tags." Electronics Letters.2007.Vol:43
[11]慈新新,王苏滨,王硕.无线射频识别(RFID)系统技术与应用.北京:人民邮电出版社,2007:3
[12]Stockman H."Communication by means of reflected power."Proceedings of the IRE,1948.Vol:36,Issue:10:1196-1204,.
[13]D.B.Harris."Radio transmission system with modulatable passive responder,"U.S.Patent.2 927321,1960
[14]R.F.Harrington."Theory of loaded scatterers," Proc.Inst.Elect.Eng.1964.Vol:111,No.4:617-623
[15]Udo Karthaus;Martin Fischerfully."Integrated passive UHF rfid transponder ic with 16.7 uw minimum RF input power."Solid-State Circuits,IEEE Journal of.2003.Vol:38,No.10:1602-1608
[16]K.V.S.Rao;Pavel V.Nikitin;SanderF.Lam."Impedance Matching Concepts in RFID Transponder Design." Automatic Identification Advanced Technologies,Fourth IEEE Workshop.2005:39-42
[17]K.V.Seshagiri Rao;Pavel V.Nikitin;Sander F.Lam."Antenna design for UHF RFID tags:a review and a practical application." IEEE Transactions on Antennas and Propagation.2005.Vol:53,No.12:3870-3876
[18]Pavel V.Nikitin;K.V.S.Rao."Reply to 'Comments on Antenna Design for UHF RFID Tags A Review and a Practical Application'." IEEE Transactions on Antennas and Propagation.2006.Vol:54,No.6:1906-1907
[19]卢万铮.天线理论与技术.西安:西安电子科技大学出版社,2004:231-233
[20]吕英华.计算电磁学的数值方法.北京:清华大学出版社,2004:260
[21]Li Yang;S.Serkan Basat;Manos M.Tentzeris."Design and Development of Novel Inductively Coupled RFID Antennas." Antennas and Propagation Society International Symposium.2006:1035-1038
[22]Tikhov Y;Yongjin Kim;Young-Hoon Min."A novel small antenna for passive RFID transponder" Microwave Conference,European.2OO5.Vol:1:4
[23]Yuri Tikhov;Yongjin Kim;Young-Hoon Min."Compact Low Cost Antenna for Passive RFID Transponder." Antennas and Propagation Society International Symposium.2006:1015-1018
[24]C.C.Chang;Y.C.Lo."Broadband RFID tag antenna with capacitively coupled structure."Electronics Letters.2006.Vol:42,Issue 23:1322-1323
[25]Ibrahiem A;Tan-Phu Vuong;Ghiotto A;Tedjini S."New design antenna for RFID UHF tags."Antennas and Propagation Society International Symposium 2006,IEEE.2006:1355-1358
[26]Yamada Y;Jung W.H;Naobumi Michishita."Extremely Small Antennas for RFID Tags."Communication systems,2006.ICCS 2006.10th IEEE Singapore International Conference on.Singapore.2006:1-5
[27]Jeon S;Yu Y;Choi J."Dual-band slot-coupled dipole antenna for 900MHz and 2.45 GHz RFID tag application" Electronics Letters.2006.Vol:42:1259-1260
[28]Zhang M.T;Jiao Y.C;Zhang F.S."Dual-band CPW-fed folded-slot monopole antenna for RFID application" Electronics Letters.2006.Vol:42:1193-1194
[29]L.S.Chan;K.W.Leung;R.Mittra;K.V.S.Rao."Platform-tolerant Design for an RFID Tag Antenna".Anti-counterfeiting,Security,Identification,2007 IEEE International Workshop.Xizmen,China.2007:57-60
[30]Pavel V.Nikitin;Sander Lam;K.V.S.Rao."Low Cost Silver Ink RFID Tag Antennas."Antennas and Propagation Society International Symposium 2005,IEEE.2005:353-356
[31]Pavel V.Nikitin;K.V.Seshagiri Rao;Sander F.Lam;Vijay Pillai;Rene Martinez;Harley Heinrich."Power Reflection Coefficient Analysis for Complex Impedances in RFID Tag Design." Microwave Theory and Techniques,IEEE Transactions.Vol:53,Issue:9.2005:2721-2725
[32]Steven M.Weigand."Compact Microstrip Antenna with Forward-Directed Radiation Pattern for RFID Reader Card." Antennas and Propagation Society International Symposium,2005IEEE.2005:337-340
[33]Choon Sac Lee;Nalbandian V."Planar circularly polarized microstrip antenna with a single feed." Antennas and Propagation,IEEE Transactions.1999.Vol:47,Issue:6:1005-1007
[34]Suwalak R;Phongcharoenpanich C."Circularly polarized truncated planar antenna with single feed for UHF RFID reader." Communications,2007.APCC 2007.Asia-Pacific Conference on.Bangkok.2007:103-106
[35]Nasimuddin;Esselle K.P;Verma A.K."Wideband High-Gain Circularly Polarized Stacked Microstrip Antennas With an Optimized C-Type Feed and a Short Horn." Antennas and Propagation,IEEE Transactions.2008.Vol:56,Issue:2:578-581
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